1. Field of the Invention
The present invention relates to systems and methods for water remediation and biosolids collection, and, more particularly, to such systems and methods for remediating water and collecting water-borne solids using solids entrapment.
2. Description of Related Art
Dissolved air flotation (DAF) is a liquid process technology that uses micro-bubble airflotation to raise and remove suspended solids in an aqueous solution such as industrial process water, municipal waste water, and/or lake water.
DAF systems known in the art are constructed from steel or concrete tanks. Large liquid above-ground vessels require structural steel plate and backing stiffeners to preclude deformation of the tank walls during hydrostatic loading when full to operating levels. The steel vessels also require footings to transfer loads to soil with appropriate bearing capacities. Inert materials like 314 and 316 Stainless Steel or exotic epoxy coating systems are typically used to retard corrosion.
Wind mixing of shallow lakes causes loose non-photosynthetic sediment material to rise into the photic zone temporarily. This reactive nutrient-laden sediment often feeds the algae in the photic zone of an impaired (hypereutrophic) lake and causes a perpetual algal bloom, which can in some cases even be seen from space (the orbiting Space Shuttle can differentiate hypertrophic Lake Apopka in Florida from other lakes, for example). One means of water remediation is to remove, or harvest, suspended solids (SS) and the nutrients incorporated thereinto.
Traditional approaches for SS removal use large expanses (5,000-45,000 acres) of flooded wetland filters where quiescent conditions cause the SS to sink out and form soil. As soil decays, much of the settled-out nutrients go back into solution, causing inefficiency. If toxic cyanobacteria algae settle out in the wetland, toxins can become available to wildlife for years, both in soil and water. Still, this has been a preferred method for remediation where a great expanse of land is available.
A known difficulty in remediating water bodies is that systems must often operate where the soil is soft and wet, for example, adjacent or on lake shores. The expense associated with providing excavation, fill, and soil stabilization can be prohibitive, and the result unsightly in an area that is supposed to be being improved. Therefore, DAF systems have been considered unsuitable for on-site water body remediation. In addition, for at least some of the same reasons, using DAF technology in a water body has not been considered to be practicable.
Prior known DAF systems require a precise balancing of criteria such as inflow rate, coagulant delivery parameters, and sludge and flotation removal in order to function effectively. As larger DAF systems are known to be prohibitively expensive, the trend has been towards smaller vessels having specific geometries for optimizing filtration.
Other problems faced at the present time are the growing expense and decreasing supplies of fuel, and the disposal of biomass generated by bioremediation systems such as algal floways and other aquatic plant systems.
Therefore, it would be desirable to provide a system and method for remediating a body of water that is economical and effective, and that does not disturb an aesthetic appeal of the water body and the surrounding area. It would also be desirable to provide a system and method for disposing of collected biosolids and for generating fuel therefrom.